<!DOCTYPE html>
<html lang="zh" dir="ltr" class="client-nojs">
<head>
<title>可分析性</title>
<meta charset="UTF-8">
<meta name="generator" content="MediaWiki 1.21.2">
<link rel="shortcut icon" href="../../../common/favicon.ico">
<link rel="stylesheet" href="../../../common/ext.css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" href="../../../common/site_modules.css">
<style>a:lang(ar),a:lang(ckb),a:lang(fa),a:lang(kk-arab),a:lang(mzn),a:lang(ps),a:lang(ur){text-decoration:none}#toc{display:none}.editsection{display:none}
/* cache key: mwiki1-mwiki_zh_:resourceloader:filter:minify-css:7:15cea3ec788a65b5187d4018eed543bf */</style>

<script src="../../../common/startup_scripts.js"></script>
<script>if(window.mw){
mw.config.set({"wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"c/language/analyzability","wgTitle":"c/language/analyzability","wgCurRevisionId":46189,"wgArticleId":7976,"wgIsArticle":true,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":[],"wgBreakFrames":false,"wgPageContentLanguage":"zh","wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"zh","wgMonthNames":["","1月","2月","3月","4月","5月","6月","7月","8月","9月","10月","11月","12月"],"wgMonthNamesShort":["","1月","2月","3月","4月","5月","6月","7月","8月","9月","10月","11月","12月"],"wgRelevantPageName":"c/language/analyzability","wgUserVariant":"zh","wgRestrictionEdit":[],"wgRestrictionMove":[]});
}</script><script>if(window.mw){
mw.loader.implement("user.options",function(){mw.user.options.set({"ccmeonemails":0,"cols":80,"date":"default","diffonly":0,"disablemail":0,"disablesuggest":0,"editfont":"default","editondblclick":0,"editsection":0,"editsectiononrightclick":0,"enotifminoredits":0,"enotifrevealaddr":0,"enotifusertalkpages":1,"enotifwatchlistpages":0,"extendwatchlist":0,"externaldiff":0,"externaleditor":0,"fancysig":0,"forceeditsummary":0,"gender":"unknown","hideminor":0,"hidepatrolled":0,"imagesize":2,"justify":0,"math":1,"minordefault":0,"newpageshidepatrolled":0,"nocache":0,"noconvertlink":0,"norollbackdiff":0,"numberheadings":0,"previewonfirst":0,"previewontop":1,"quickbar":5,"rcdays":7,"rclimit":50,"rememberpassword":0,"rows":25,"searchlimit":20,"showhiddencats":0,"showjumplinks":1,"shownumberswatching":1,"showtoc":0,"showtoolbar":1,"skin":"cppreference2","stubthreshold":0,"thumbsize":2,"underline":2,"uselivepreview":0,"usenewrc":0,"watchcreations":0,"watchdefault":0,"watchdeletion":0,
"watchlistdays":3,"watchlisthideanons":0,"watchlisthidebots":0,"watchlisthideliu":0,"watchlisthideminor":0,"watchlisthideown":0,"watchlisthidepatrolled":0,"watchmoves":0,"wllimit":250,"variant":"zh","language":"zh","searchNs0":true,"searchNs1":false,"searchNs2":false,"searchNs3":false,"searchNs4":false,"searchNs5":false,"searchNs6":false,"searchNs7":false,"searchNs8":false,"searchNs9":false,"searchNs10":false,"searchNs11":false,"searchNs12":false,"searchNs13":false,"searchNs14":false,"searchNs15":false,"gadget-MathJax":1,"gadget-ColiruCompiler":1});;},{},{});mw.loader.implement("user.tokens",function(){mw.user.tokens.set({"editToken":"+\\","patrolToken":false,"watchToken":false});;},{},{});
/* cache key: mwiki1-mwiki_zh_:resourceloader:filter:minify-js:7:258d7cd6aa9aa67dee25e01fb6a9e505 */
}</script>
<script>if(window.mw){
mw.loader.load(["mediawiki.page.startup","mediawiki.legacy.wikibits","mediawiki.legacy.ajax"]);
}</script>
<style type="text/css">/*<![CDATA[*/
.source-c {line-height: normal;}
.source-c li, .source-c pre {
	line-height: normal; border: 0px none white;
}
/**
 * GeSHi Dynamically Generated Stylesheet
 * --------------------------------------
 * Dynamically generated stylesheet for c
 * CSS class: source-c, CSS id: 
 * GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann
 * (http://qbnz.com/highlighter/ and http://geshi.org/)
 * --------------------------------------
 */
.c.source-c .de1, .c.source-c .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}
.c.source-c  {font-family:monospace;}
.c.source-c .imp {font-weight: bold; color: red;}
.c.source-c li, .c.source-c .li1 {font-weight: normal; vertical-align:top;}
.c.source-c .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}
.c.source-c .li2 {font-weight: bold; vertical-align:top;}
.c.source-c .kw1 {color: #0000dd;}
.c.source-c .kw2 {color: #0000ff;}
.c.source-c .kw3 {color: #0000dd;}
.c.source-c .kw4 {color: #0000ff;}
.c.source-c .co1 {color: #909090;}
.c.source-c .co2 {color: #339900;}
.c.source-c .coMULTI {color: #ff0000; font-style: italic;}
.c.source-c .es0 {color: #008000; font-weight: bold;}
.c.source-c .es1 {color: #008000; font-weight: bold;}
.c.source-c .es2 {color: #008000; font-weight: bold;}
.c.source-c .es3 {color: #008000; font-weight: bold;}
.c.source-c .es4 {color: #008000; font-weight: bold;}
.c.source-c .es5 {color: #008000; font-weight: bold;}
.c.source-c .br0 {color: #008000;}
.c.source-c .sy0 {color: #008000;}
.c.source-c .sy1 {color: #000080;}
.c.source-c .sy2 {color: #000040;}
.c.source-c .sy3 {color: #000040;}
.c.source-c .sy4 {color: #008080;}
.c.source-c .st0 {color: #008000;}
.c.source-c .nu0 {color: #000080;}
.c.source-c .nu6 {color:#000080;}
.c.source-c .nu8 {color:#000080;}
.c.source-c .nu12 {color:#000080;}
.c.source-c .nu16 {color:#000080;}
.c.source-c .nu17 {color:#000080;}
.c.source-c .nu18 {color:#000080;}
.c.source-c .nu19 {color:#000080;}
.c.source-c .ln-xtra, .c.source-c li.ln-xtra, .c.source-c div.ln-xtra {background-color: #ffc;}
.c.source-c span.xtra { display:block; }

/*]]>*/
</style><!--[if lt IE 7]><style type="text/css">body{behavior:url("/mwiki/skins/cppreference2/csshover.min.htc")}</style><![endif]--></head>
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_language_analyzability skin-cppreference2 action-view cpp-navbar">
        <!-- header -->
        <!-- /header -->
        <!-- content -->
<div id="cpp-content-base">
            <div id="content">
                <a id="top"></a>
                <div id="mw-js-message" style="display:none;"></div>
                                <!-- firstHeading -->
<h1 id="firstHeading" class="firstHeading">可分析性</h1>
                <!-- /firstHeading -->
                <!-- bodyContent -->
                <div id="bodyContent">
                                        <!-- tagline -->
                    <div id="siteSub">来自cppreference.com</div>
                    <!-- /tagline -->
                                        <!-- subtitle -->
                    <div id="contentSub"><span class="subpages">&lt; <a href="../../c.html" title="c">c</a>‎ | <a href="../language.html" title="c/language">language</a></span></div>
                    <!-- /subtitle -->
                                                            <!-- bodycontent -->
                    <div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr"><div class="t-navbar" style=""><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../../c.html" title="c"> C</a><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="line-height:1.1em;">
<tr class="t-nv"><td colspan="5"> <a href="../language.html" title="c/language">语言</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../header.html" title="c/header">头文件</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../types.html" title="c/types">类型支持</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../program.html" title="c/program">程序工具</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../variadic.html" title="c/variadic">变参数函数支持</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../memory.html" title="c/memory">动态内存管理</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../error.html" title="c/error">错误处理</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../chrono.html" title="c/chrono">日期和时间工具</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../string.html" title="c/string">字符串库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../algorithm.html" title="c/algorithm">算法</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../numeric.html" title="c/numeric">数值</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../io.html" title="c/io">输入/输出支持</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../locale.html" title="c/locale">本地化支持</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../thread.html" title="c/thread">线程支持</a> <span class="t-mark-rev t-since-c11">(C11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../atomic.html" title="c/atomic">原子操作</a> <span class="t-mark-rev t-since-c11">(C11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../experimental.html" title="c/experimental">技术规范</a> </td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../language.html" title="c/language">C 语言</a><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv-h2"><td colspan="5"> <a href="basic_concepts.html" title="c/language/basic concepts">基本概念</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="../keyword.html" title="c/keyword">关键词</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="../preprocessor.html" title="c/preprocessor">预处理器</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="statements.html" title="c/language/statements">语句</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="expressions.html" title="c/language/expressions">表达式</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="initialization.html" title="c/language/initialization">初始化</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="declarations.html" title="c/language/declarations">声明</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="functions.html" title="c/language/functions">函数</a></td></tr>
<tr class="t-nv"><td colspan="5"> 杂项</td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="history.html" title="c/language/history">C 的历史</a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> <a href="../experimental.html" title="c/experimental">技术规范</a> </td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div></div>
<p>C 语言的此扩展限制执行某些未定义行为潜在结果，它提升这种程序的静态分析效果。可分析性仅若编译器定义了<a href="../preprocessor/replace.html" title="c/preprocessor/replace">预定义宏常量</a> <span class="t-c"><span class="mw-geshi c source-c">__STDC_ANALYZABLE__</span></span> <span class="t-mark-rev t-since-c11">(C11)</span>才得到保证。
</p><p>若编译器支持可分析性，任何行为未定义的语言或库构造可以进一步分为<i>严格</i>和<i>有界</i>未定义行为，且所有有界 UB 的情况以如下方式限制。
</p>
<h3><span class="mw-headline" id=".E4.B8.A5.E6.A0.BC.E6.9C.AA.E5.AE.9A.E4.B9.89.E8.A1.8C.E4.B8.BA">严格未定义行为</span></h3>
<p>严格 UB 是可能在任何对象之外进行内存写入或易失内存丢的未定义行为。拥有严格未定义行为的程序可能受安全开发影响。
</p><p>仅下列未定义行为是严格的：
</p>
<ul><li> 在<a href="lifetime.html" title="c/language/lifetime">生存期</a>外访问对象（例如通过悬垂指针）
</li><li> 写入声明不<a href="type.html#.E5.85.BC.E5.AE.B9.E7.B1.BB.E5.9E.8B" title="c/language/types">兼容</a>的对象
</li><li> 通过与所指向类型不<a href="type.html#.E5.85.BC.E5.AE.B9.E7.B1.BB.E5.9E.8B" title="c/language/types">兼容</a>的指针调用函数
</li><li> 求值<a href="value_category.html" title="c/language/value category">左值表达式</a>，但不指代一个对象
</li><li> 试图修改<a href="string_literal.html" title="c/language/string literal">字符串字面量</a>
</li><li> <a href="operator_member_access.html" title="c/language/operator member access">解引用</a>非法（空的、不确定的等）或<a href="operator_arithmetic.html" title="c/language/operator arithmetic">尾后</a>指针
</li><li> 通过非 const 指针修改 <a href="const.html" title="c/language/const">const对象</a>
</li><li> 以非法参数调用标准库函数或宏
</li><li> 以不期待的类型调用变参数的标准库函数（例如以不匹配其转换指定符的参数调用 <span class="t-lc"><a href="../io/fprintf.html" title="c/io/fprintf">printf</a></span> ）
</li><li> <span class="t-lc"><a href="../program/longjmp.html" title="c/program/longjmp">longjmp</a></span> ，其中 <span class="t-lc"><a href="../program/setjmp.html" title="c/program/setjmp">setjmp</a></span> 不在调用方作用域、跨线程，或在动态修改（ VM ）类型的作用域中。
</li><li> 使用任何被 <span class="t-lc"><a href="../memory/free.html" title="c/memory/free">free</a></span> 或 <span class="t-lc"><a href="../memory/realloc.html" title="c/memory/realloc">realloc</a></span> 解分配的指针
</li><li> 任何<a href="../string/byte.html" title="c/string/byte">字符串</a>或<a href="../string/wide.html" title="c/string/wide">宽字符串</a>函数访问边界外的数组
</li></ul>
<h3><span class="mw-headline" id=".E6.9C.89.E7.95.8C.E6.9C.AA.E5.AE.9A.E4.B9.89.E8.A1.8C.E4.B8.BA">有界未定义行为</span></h3>
<p>有界 UB 是不能进行非法内存写、读的未定义行为，尽管内存可能是陷阱表示或存储不确定值。
</p>
<ul><li> 任何不列作严格的未定义行为是有界的，包括
</li></ul>
<dl><dd><ul><li> 多线程数据竞争
</li><li> 使用拥有自动存储期的<a href="initialization.html" title="c/language/initialization">不确定值</a>
</li><li> <a href="object.html#.E4.B8.A5.E6.A0.BC.E5.88.AB.E5.90.8D.E4.BD.BF.E7.94.A8" title="c/language/object">别名使用</a>违规
</li><li> <a href="object.html#.E5.AF.B9.E9.BD.90" title="c/language/object">错误对齐</a>的对象访问
</li><li> 有符号整数溢出
</li><li> 修改或修改及读取同一个标量的<a href="eval_order.html" title="c/language/eval order">无顺序副效应</a>
</li><li> 浮点到整数或指针到整数<a href="conversion.html" title="c/language/conversion">转换</a>溢出
</li><li> 以负值或过大位数<a href="operator_arithmetic.html" title="c/language/operator arithmetic">逐位左移</a>
</li><li> 除以零的<a href="operator_arithmetic.html" title="c/language/operator arithmetic">整数除法</a>
</li><li> 使用 void 表达式
</li><li> 不准确重叠对象的直接<a href="operator_assignment.html" title="c/language/operator assignment">赋值</a>或 <span class="t-lc"><a href="../string/byte/memcpy.html" title="c/string/byte/memcpy">memcpy</a></span>
</li><li> <a href="restrict.html" title="c/language/restrict">restrict</a> 违规
</li><li> 等等……所有不在严格列表中的未定义行为。
</li></ul>
</dd></dl>
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
<p>有界未定义行为禁用某些优化：有可分析性的编译保留源代码因果性，否则它会被某些未定义行为<a href="https://zh.cppreference.com/mwiki/index.php?title=c/language/as_if&amp;action=edit&amp;redlink=1" class="new" title="c/language/as if（页面不存在）">违规</a>。
</p><p>可分析性扩展，允许在陷阱出现时调用<a href="../error/set_constraint_handler_s.html" title="c/error/set constraint handler s">运行时制约处理</a>，作为一种实现定义行为的形式。
</p>
<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">引用</span></h3>
<div class="t-ref-std-11">
<ul><li> C11 standard (ISO/IEC 9899:2011): 
</li></ul>
<dl><dd><ul><li> 6.10.8.3/1 Conditional feature macros (p: 177)
</li></ul>
</dd></dl>
<dl><dd><ul><li> Annex L Analyzability (p: 652-653)
</li></ul>
</dd></dl>
</div>

<!-- 
NewPP limit report
Preprocessor visited node count: 898/1000000
Preprocessor generated node count: 2792/1000000
Post‐expand include size: 21763/2097152 bytes
Template argument size: 2463/2097152 bytes
Highest expansion depth: 13/40
Expensive parser function count: 0/100
-->

<!-- Saved in parser cache with key mwiki1-mwiki_zh_:pcache:idhash:7976-0!*!0!!zh!*!zh!* and timestamp 20200219085150 -->
</div>                    <!-- /bodycontent -->
                                        <!-- printfooter -->
                    <div class="printfooter">
                    来自“<a href="https://zh.cppreference.com/mwiki/index.php?title=c/language/analyzability&amp;oldid=46189">https://zh.cppreference.com/mwiki/index.php?title=c/language/analyzability&amp;oldid=46189</a>”                    </div>
                    <!-- /printfooter -->
                                                            <!-- catlinks -->
                    <!-- /catlinks -->
                                                            <div class="visualClear"></div>
                    <!-- debughtml -->
                                        <!-- /debughtml -->
                </div>
                <!-- /bodyContent -->
            </div>
        </div>
        <!-- /content -->
        <!-- footer -->
        <div id="cpp-footer-base" class="noprint">
            <div id="footer">
                        <div id="cpp-navigation">
            <h5>导航</h5>
            <ul><li><a href="https://zh.cppreference.com/w/c/language/analyzability">Online version</a></li><li>Offline version retrieved 2020-03-14 18:00.</li></ul></div>
                        <ul id="footer-info">
                                    <li id="footer-info-lastmod"> 本页面最后修改于2017年9月5日 (星期二) 01:53。</li>
                                    <li id="footer-info-viewcount">此页面已被浏览过1,645次。</li>
                            </ul>
                    </div>
        </div>
        <!-- /footer -->
        <script>if(window.mw){
mw.loader.state({"site":"loading","user":"missing","user.groups":"ready"});
}</script>
<script src="../../../common/skin_scripts.js"></script>
<script>if(window.mw){
mw.loader.load(["mediawiki.action.view.postEdit","mediawiki.user","mediawiki.page.ready","mediawiki.searchSuggest","mediawiki.hidpi","ext.gadget.MathJax","ext.gadget.ColiruCompiler"], null, true);
}</script>
<script src="../../../common/site_scripts.js"></script>
<script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-2828341-1']);
_gaq.push(['_setDomainName', 'cppreference.com']);
_gaq.push(['_trackPageview']);
</script><!-- Served in 0.253 secs. -->
	</body>
<!-- Cached 20200219085150 -->
</html>